Pyridazine

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Pyridazine
Skeletal formula with numbering convention
Pyridazine molecule Pyridazine molecule
Identifiers
CAS number 289-80-5 YesY
PubChem 9259
ChemSpider 8902 YesY
ChEBI CHEBI:30954 YesY
ChEMBL CHEMBL15719 YesY
RTECS number GY2390000
Jmol-3D images Image 1
Properties
Molecular formula C4H4N2
Molar mass 80.09 g mol−1
Appearance colorless liquid
Density 1.107 g/cm3
Melting point −8 °C (18 °F; 265 K)
Boiling point 208 °C (406 °F; 481 K)
Related compounds
Related compounds pyridine, pyrimidine, pyrazine
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Pyridazine is a heterocyclic organic compound with the molecular formula (CH)4N2. It contains a six-membered ring with two adjacent nitrogen atoms, and is aromatic.[1] It is a colorless liquid with a boiling point of 208 °C. It is isomeric with two other (CH)4N2 rings, pyrimidine and pyrazine.

Occurrence[edit]

Pyridazines are rare in nature, possibly reflecting the scarcity of naturally occurring hydrazines, common building blocks for the synthesis of these heterocycles. The pyridazine structure is a popular pharmacophore. It found within a number of herbicides such as credazine, pyridafol and pyridate. It is also found within the structure of several drugs such as cefozopran, cadralazine, minaprine, pipofezine, hydralazine, and cilazapril.

Syntheses[edit]

In the course of his classic investigation on the Fischer indole synthesis, Emil Fischer prepared the first pyridazine via the condensation of phenylhydrazine and levulinic acid.[2] The parent heterocycle was first prepared by oxidation of benzocinnoline to the pyridazinetetracarboxylic acid followed by decarboxylation. A better route to this otherwise esoteric compound starts with the maleic hydrazide. These heterocycles are often prepared via condensation of 1,4-diketones or 4-ketoacids with hydrazines.[3]

References[edit]

  1. ^ S. Gumus, "A computational study on substituted diazabenzenes," Turk J Chem, 35 (2011) , 803 – 808; http://journals.tubitak.gov.tr/chem/issues/kim-11-35-5/kim-35-5-11-1012-875.pdf
  2. ^ E. Fischer "Indole aus Phenylhydrazin" Justus Liebigs Annalen der Chemie 1886, Volume 236, Issue 1-2, pages 126–151. doi:10.1002/jlac.18862360107
  3. ^ M. Tišler, B. Stanovnik "Pyridazines" Advances in Heterocyclic Chemistry, Volume 9, 1968, Pages 211-320. http://dx.doi.org/10.1016/S0065-2725(08)60374-8